Both are seeking a doctorate at the University of California, Davis. They differ in that Winokur focuses her research primarily on the yellow-fever mosquito, Aedes aegypti, while Portilla's research involves Culex mosquitoes, which transmit West Nile virus and other diseases.

They are alike in that they share the passion of the late William Emery Hazeltine (1926-1994), who worked tirelessly in mosquito research and public health.

Hazeltine, a native of San Jose, was a U.S. Navy veteran who studied entomology at UC Berkeley and received his doctorate in entomology from Purdue University in 1962. He managed the Butte County Mosquito Abatement District, Oroville, from 1966 to 1992, and the Lake County Mosquito Abatement District from 1961-1964.

He was an ardent supporter of the judicious use of public health pesticides to protect public health, remembers Bruce Eldridge, emeritus professor of entomology at UC Davis and former director of the (now folded) statewide UC Mosquito Research Program. Eldridge eulogized him at the 2005 annual meeting of the American Mosquito Control Association (AMCA) as "a man who made a difference." The AMCA journal published his eulogy in its 2006 edition. (See http://entomology.ucdavis.edu/files/154217.pdf)

"Bill was a medical entomologist who had a varied career in the field of mosquito biology and control, but he will forever be remembered as a man who fought in the trenches of the pesticide controversy from 1960 until the end of his life, and who made the safe and efficient use of pesticides in public health a personal crusade," Eldridge said.

In his memory, his three sons--Craig Hazeltine of Scottsdale, Ariz., Lee Hazeltine of Lincoln, formerly of Woodland, and the late Jeff Hazeltine (1958-2013)—established the UC Davis Bill Hazeltine Graduate Student Research Awards, awarding the first one in 1997. Each year they travel to Davis to honor the recipients at a luncheon, timed with their attendance at a scholarship and fellowship celebration, hosted by Dean Helene Dillard, UC Davis College of Agricultural and Environmental Science.

Winokur, who studies with advisor Christopher Barker of the Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, received $2425, and Maribel “Mimi” Portilla, who studies with major professor Sharon Lawler, UC Davis Department of Entomology and Nematology, received $2032.

“Aedes aegypti and Aedes albopictus are mosquitoes capable of transmitting dengue, chikungunya, yellow fever, and Zika viruses,” Winokur explained in her application. “These species are invasive and present in California and continue to spread, increasing the likelihood of local transmission of these devastating viruses. Additionally, Aedes notoscriptus, an Australian mosquito whose vector competence for many viruses is unknown, has been detected in Los Angeles and is likely to spread in the state. Aedesmosquitoes are readily detected using ovitraps, a cheap and effective sampling method to detect the presence of gravid females. Ovitraps are especially useful when mosquito populations are low as traps for adult Aedes are unreliable. Once collected, the eggs cannot be differentiated using a stereomicroscope. Traditionally, identifying Aedes eggs collected in ovitraps requires hatching and rearing to adult for visual identification, which is time consuming and leads to a time lag for control, potentially allowing invasive species to spread without intervention.”

“Currently, I am developing a non-destructive, low-cost method to rapidly identify Aedes eggs,” Winokur wrote. “I have shown that species-specific surface morphologies of the exochorion can be used to differentiate species using electron microscopy. This method is expensive and therefore not a realistic surveillance technique. We can, however, exploit these species-specific surface morphologies in another way to identify Aedeseggs. Slight changes in morphological characteristics can be captured with high spatial resolution proximal sensing imaging, termed hyperspectral imaging.”

Winokur is testing “the use of hyperspectral imaging to differentiate between eggs collected from lab colonies of native and invasive Aedes mosquitoes in California. Preliminary data indicate this method shows promise for identifying species and warrants further testing. Once I have created species-specific reflectance profiles and validated my identification method using colony eggs, I will collect field eggs and validate the identification method using these field eggs.” She is working with hyperspectral imaging expert Christian Nansen, agricultural entomologist and assistant professor, UC Davis Department of Entomology and Nematology, on the project.

Winokur describes hyperspectral imaging as “a powerful tool that recognizes slight changes; therefore, we need to ensure that all samples are collected and conditioned the same way before testing. Samples must be imaged directly on the oviposition paper because exochorion cells are damaged by the ‘glue' the female uses to attach her eggs to the substrate; imaging removed eggs leads to inconsistent reflectance profiles. This method for rapidly identifying Aedes eggs will allow for quick response to the detection of invasive Aedes mosquitoes.”

Winokur is using the 2017 Hazeltine funds to improve identification of invasive Aedes mosquito eggs in California and to attend the 2017 American Society of Tropical Medicine and Hygiene conference. She is also the newly announced recipient of a 2018 Hazeltine Student Research Award for $3,094, this time to investigate Aedes aegypti immune response to Zika virus.

A native of Long Beach, Calif., Olivia grew up in Laguna Niguel, Calif., where she focused on science at the Dana Hills High School Health and Medical Occupations Academy. She received her bachelor's degree in 2015 from Cornell University, majoring in Interdisciplinary Studies and focusing on the environmental effects on human health. She enrolled in the UC Davis graduate program in 2016 as a Ph.D entomology student with a designated emphasis in the biology of vector-borne diseases. Earlier this year, Winokur received a three-year National Science Foundation Graduate Research Fellowship.

After finishing her Ph.D., Winokur plans to remain in academia, but “I'm unsure exactly what that will look like! I really enjoy research, teaching, and mentoring so I'd like to have a career where I can do all of these. I also plan to have a career where I can conduct translational research with broad global health implications, engage non-scientists, create tools to help decision makers mitigate vector-borne disease burden worldwide, and encourage interest and diversity in STEM (science, technology, engineering and mathematics).”

Maribel Portilla, currently writing her dissertation, said the three chapters will encompass: the management practices of the invasive exotic weeds, Brazilian waterweed (Egeria densa) and water hyacinth (Eichhornia crassipes), in the Sacramento-San Joaquin Delta and how those practices impact mosquitoes and their habitat; herbicide use in managing those weeds and how herbicides affects the larval habitat; and the direct effects of herbicides on larval mosquito development.

Her goal: “to inform and create better techniques to reduce both mosquito and weed problems."

Like Winokur, Portilla is grateful for the Hazeltine research funds. “I am currently exploring some molecular/genetic techniques (PCR and sequencing) to identify the species of mosquitoes I collected in the different weed/habitat mesocosms, This will be funded by the Hazeltine award I received.”

Portilla, who calls the South Bay home (San Martin, Santa Clara County), holds a master's degree in public health from UC Berkeley, where “I was able to study health and disease within a larger context, and learned to consider the biological and the social determinants of disease.” Her area of expertise incorporates her love for biology and her strong interest in social issues.

“At UC Berkeley School of Public Health, I was able to study health and disease within a larger context, and learned to consider the biological and the social determinants of disease. As I completed my degree, I realized I really missed the research experiences I had as an undergraduate. So, I looked for a way to bridge my new-found passion for public health and basic science research. This led me to UC Davis, where I learned about One Health and am now pursuing a Ph.D in medical entomology. Medical entomology is a perfect example of a One Health field, where I can seek out how interactions between humans and animals impact health. I am particularly interested in researching how disease risk may change as people manipulate the environment."

Portilla, who joined the UC Davis Entomology Graduate Program in the fall of 2012, anticipates receiving her doctorate “in six to 12 months.”

Her academic life revolves around writing her dissertation; teaching UC Davis classes (she's taught entomology, general biology and One Health classes); research; and public outreach. Since 2012, she has mentored some 30 undergraduate students on developing and executing their research experiments. She praised the “the diversity of my interns; they each brought such important and unique perspectives to the project.”

What are her career plans?

“Due to my diverse interests and skill set, I am very open about my career choices. I have extensive teaching experience, and would love to be a professor with both teaching and research opportunities. However, there are many opportunities beyond academia. My research is introducing me to many other ways in which my work and research can help keep people safe and healthy. I hope to develop a strong research skill set while at UC Davis, and find a career path which takes advantage of my diverse abilities and love for One Health and Public Health."

Portilla mentioned pursuing a career as a teacher in a small liberal arts school to teach public health, general biology and global diseases classes, as well as do outreach and research. “I'm more of a scientist than an entomologist,” she said.

Portilla may also pursue a career working in vector-control health education at the county, district or state level. “I'm open at this point,” she said. Overall, she is geared toward improving public health outcomes through healthier environments. “I care about how outcomes affect the larger population,” she said.

“Bill Hazeltine was an advocate for the use of mosquito control to protect people from mosquitoes and the disease agents they transmit, and he believed chemical control to be a necessary part of the means to accomplish this,” wrote Eldridge, who valued his friendship. “He also considered himself an environmentalist, and billed himself as such on his business cards and on his signature block. He had a vast knowledge of pesticides and pesticide legislation, and a strong belief in the scientific basis for public policy issues related to the safe and effective use of pesticides. Because the federal Endangered Species Act influenced mosquito control, he became an authority on this as well."

“After Bill's death, I was contacted by his sons about the possibility of establishing a William Hazeltine Memorial Scholarship Fund at UC Davis,” Eldridge noted. “They believed this would represent an important contribution because of Bill's strong interest and support of medical entomology research, and because of Bill's admiration of UC programs in mosquito control. The fund has grown to the point where graduate student awards can now be funded just from the interest, and a number of students at UCD have benefited from the thoughtfulness of the Hazeltine family.”

UC Davis doctoral student and mosquito researcher Olivia Winokur remembers the defining moment when she learned that mosquitoes are “much more than just annoying.”

In fact, it was her childhood curiosity about a yellow fever vaccination that sparked her interest in mosquitoes.

In her youth, Olivia traveled with her parents and brothers to “off-the-beaten-path” locations. “So I was exposed to vector-borne disease awareness from a young age,” she recalled. “When I was 8 years old, I remember getting the yellow fever vaccination and being curious about why I had to get it for a trip to Southern Africa. I think that was my defining moment when I learned mosquitoes are more than just annoying. Since then, I've slept under many mosquito nets and am no stranger to mosquito bites.”

“I didn't think much about making a career out of those 'skeeters, though. I attended Cornell University as undergraduate, where I studied global public health from multiple perspectives. It wasn't until I became a research assistant in Dr. Laura Harrington's lab that I became fascinated with mosquito biology and decided to pursue a career in medical entomology.”

Winokur, who received her bachelor's degree in 2015 from Cornell University, majoring in Interdisciplinary Studies and focusing on the environmental effects on human health, enrolled in the UC Davis graduate program in 2016 as a Ph.D entomology student with a designated emphasis in the biology of vector-borne diseases.

She studies with major professor and UC Davis alumnus Christopher Barker, associate professor and associate researcher in the Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, who doubles as a graduate student advisor in the UC Davis Department of Entomology and Nematology.

Earlier this year, Winokur received a three-year National Science Foundation Graduate Research Fellowship. A 2017 Bill Hazeltine Memorial Award also helps fund her research.

Her research at UC Davis mainly involves Aedes aegypti, also known as the yellow fever mosquito. “At present, most of the research done on mosquito-borne virus transmission is done under a very narrow range of conditions that reflect a particular mosquito species' 'optimal' rearing and adult environment,” Winokur said. “I'm interested in how conditions outside of this optimal range at both the larval and adult stages affect mosquito-borne virus transmission. I work mostly with Aedes aegypti, which transmits diseases including dengue, Zika, yellow fever, and chikungunya viruses. Currently my research is focused on Zika virus. I hope to determine how the range of conditions mosquitoes encounter outside of the lab alter their life history traits, such as survival and blood feeding behavior, as well as viral transmission so that we can better understand geographical and seasonal mosquito-borne virus risk and eventually mitigate the risk.”

A typical day in the lab: “My days are usually a bit all over the place--I typically spend some time in the BSL-3 (Biosafety Level 3) either collecting samples from infected mosquitoes or processing previously collected samples, some time back in the lab analyzing data and writing, and I'm still taking classes so a few days a week I spend the afternoon on the main campus.”

What fascinates her about mosquitoes? “People are usually wowed when I tell them there are over 3500 species of mosquitoes!” she said. “But don't worry.. not all of them transmit human pathogens. I love telling people about the natural history of different genera and species and how this affects the likelihood of pathogen transmission to humans. I'm continually fascinated by how resilient mosquitoes are, how successful they've been throughout history, and how they've completely altered human history. I actually gave a lecture on how vector-borne diseases have altered human history last quarter (Winter 2018) to an undergraduate class led by UC Davis entomology graduate students (Ent10: Natural History of Insects).”

Born in Long Beach, Calif., Olivia grew up in Laguna Niguel, Calif., where she focused on science as a part of the Dana Hills High School Health and Medical Occupations Academy. Olivia also played basketball at Dana Hills and helped the team win its first league title.

What drew her to UC Davis? “I grew up in California so I was familiar with UC Davis from a young age. I actually applied to UC Davis as an undergraduate, but decided to try life on the East Coast instead and attended Cornell University. While at Cornell, I learned a lot about UC Davis as most of my professors had spent some time at UC Davis during their academic tenure, and a lot of the research I was reading was coming out of UC Davis. I was excited to come back to the West Coast for graduate school so UC Davis seemed like an obvious choice!”

While at Cornell, she interned at the National Institutes of Health (NIH) in 2014, when advised by John Balbus of National Institute of Environmental Health Sciences (NIEHS), and Joshua Rosenthal, Fogarty International Center, where she coordinated and wrote an interagency proposal for climate change mitigation in middle and low-income countries under the United Nations. "I also helped develop a global clean cook stove implementation framework to advise NIH initiatives,” she said.

Winokur is a co-author of “The Impact of Temperature and Body-Size on Flight Tone Variation in the Mosquito Vector Aedes aegypti (Diptera: Culicidae): Implications for Acoustic Lures," published in April 2017, in the Journal of Medical Entomology. Several other manuscripts are accepted or in preparation.

She has given presentations at the Mosquito and Vector Control Association of California and the American Society of Tropical Medicine and Hygiene.

Dedicated to helping high school girls transition into STEM (Science, Technology, Engineering and Math) careers, Winokur is a founding board member and publicity co-chair of GOALS (Girls' Outdoor Adventure in Leadership and Science). The organization seeks “to cultivate and embolden the next generation of STEM leaders through a free, immersive, field-based summer science program for high school girls.”

“GOALS is for high school girls, inclusive of cis, trans, and gender nonbinary youth who identify with girlhood, to learn science hands-on while backpacking through the wilderness,” Winokur related. “I have worked with an incredible team of UC Davis affiliates to create GOALS to increase opportunities for high school students who identify with girlhood from backgrounds traditionally underrepresented in STEM. Our first trip is happening this summer!” This year's program takes place July 21 to Aug. 5.

Winokur is also a part of the Letters to a Pre-Scientist program “so I get to be a pen-pal to an elementary school student to talk about science!” In addition, she serves as the treasurer of the UC Davis Entomology Graduate Student Association.

Delighted to return to California after being on the East Coast, Winokur spends her leisure time outdoors hiking and backpacking “and exploring the beautiful places near Davis like the Lake Tahoe area and Yosemite. I taught backpacking and wilderness survival skills for Cornell Outdoor Education during college. Additionally, I'm a trivia nerd so I watch a lot of Jeopardy! and play pub trivia with my entomology colleagues weekly. I also enjoy drawing, reading, playing board games, and doing jigsaw puzzles. When I get the chance I enjoy traveling as well--I just returned from Belize and I'll be in Denmark in July!”

After finishing her Ph.D., Winokur plans to remain in academia, but “I'm unsure exactly what that will look like! I really enjoy research, teaching, and mentoring so I'd like to have a career where I can do all of these. I also plan to have a career where I can conduct translational research with broad global health implications, engage non-scientists, create tools to help decision makers mitigate vector-borne disease burden worldwide, and encourage interest and diversity in STEM.”